%channel_db_files = (
          'ch1' => {
                     '00010' => '/foo/oradata/bar/foodb-lob01.dbf',
                     '00004' => '/foo/oradata/bar/foodb-data02.dbf',
                     '00007' => '/foo/oradata/bar/undotbs02.dbf'
                   },
          'ch2' => {
                     '00003' => '/foo/oradata/bar/tools01.dbf',
                     '00006' => '/foo/oradata/bar/foodb-index11.dbf',
                     '00002' => '/foo/oradata/bar/undotbs01.dbf'
                   },
          'ch3' => {
                     '00005' => '/foo/oradata/bar/xml01.dbf',
                     '00009' => '/foo/oradata/bar/foodb-index01.dbf',
                     '00001' => '/foo/oradata/bar/system01.dbf',
                     '00008' => '/foo/oradata/bar/foodb-data01.dbf'
                   }
);

##</code><code>##

#----------------8<----------------
#!/usr/bin/perl

use strict;
use Data::Dumper;

my %channel_db_files = ();
my $RMAN_NO_OF_CHANNELS = 3;
my $RMAN_RUN_CH_NAME = 'ch';

LOOP: while (<DATA>) {
    chomp;
    
    foreach my $i ( 1 .. ${RMAN_NO_OF_CHANNELS} ) {
        
        if ( /$RMAN_RUN_CH_NAME$i/ ) {
            while (<DATA>) {
                chomp;
                 
                if ( /^input datafile/ ) {
                    my ($file_number, $file_name) = $_ =~ /number=(\d+)\s+name=(.*)/;
                    $channel_db_files{"ch$i"}{$file_number} = $file_name;
                } else {
                    redo LOOP;
                }
            }
        }
    }
}


print Dumper \%channel_db_files;


__DATA__
Starting backup at 2011-05-31 02:00:05
channel ch1: starting compressed full datafile backup set
channel ch1: specifying datafile(s) in backup set
input datafile file number=00010 name=/foo/oradata/bar/foodb-lob01.dbf
input datafile file number=00004 name=/foo/oradata/bar/foodb-data02.dbf
input datafile file number=00007 name=/foo/oradata/bar/undotbs02.dbf
channel ch1: starting piece 1 at 2011-05-31 02:00:06
channel ch2: starting compressed full datafile backup set
channel ch2: specifying datafile(s) in backup set
input datafile file number=00003 name=/foo/oradata/bar/tools01.dbf
input datafile file number=00006 name=/foo/oradata/bar/foodb-index11.dbf
input datafile file number=00002 name=/foo/oradata/bar/undotbs01.dbf
channel ch2: starting piece 1 at 2011-05-31 02:00:06
channel ch3: starting compressed full datafile backup set
channel ch3: specifying datafile(s) in backup set
input datafile file number=00008 name=/foo/oradata/bar/foodb-data01.dbf
input datafile file number=00009 name=/foo/oradata/bar/foodb-index01.dbf
input datafile file number=00005 name=/foo/oradata/bar/xml01.dbf
input datafile file number=00001 name=/foo/oradata/bar/system01.dbf
channel ch3: starting piece 1 at 2011-05-31 02:00:07
channel ch1: finished piece 1 at 2011-05-31 02:34:54
#----------------8<----------------

##</code><code>##

----- ----------------------------------------
File# File Name
----- ----------------------------------------
1     /foo/oradata/bar/system01.dbf          
2     /foo/oradata/bar/undotbs01.dbf        
3     /foo/oradata/bar/tools01.dbf          
4     /foo/oradata/bar/foodb-data02.dbf        
5     /foo/oradata/bar/xml01.dbf             
6     /foo/oradata/bar/foodb-index11.dbf       
7     /foo/oradata/bar/undotbs02.dbf         
8     /foo/oradata/bar/foodb-data01.dbf       
9     /foo/oradata/bar/foodb-index01.dbf      
10    /foo/oradata/bar/foodb-lob01.dbf